Budgeting the Impact of Inflectra and a Possible Clinical Benefit for Amjevita

Although the biosimilar marketplace is fairly stagnant at the moment, there was plenty of action at this week’s annual meeting of the Academy of Managed Care Pharmacy held in Denver, March 27–30.

Calculating the Breakeven Point for a Health System

A poster presentation from the University of Pittsburgh School of Pharmacy discussed the budget impact of adding biosimilar infliximab (Inflectra®) to the formulary of a model health system.

In this presentation, the researchers assumed the health system had 1,000 patients taking infliximab; of these, 400 were new prescription starts for the biosimilar’s rheumatology and gastroenterological indications, and the rest were receiving maintenance therapy on the originator product Remicade®. The model assumed 3 levels of discounting on Remicade: 10%, 15%, and 20%. They assumed that 60% of patients with a gastrointestinal indication would start on Remicade, and 40% of new start patients would be given Inflectra. At a new start and maintenance price of $20,430 for the biosimilar, they calculate a breakeven point of 15% discount for Remicade to keep only the originator on formulary.

If they assumed that the biosimilar was given not only to new starts but also to 50% of patients initially receiving Remicade , the breakeven discounting point for keeping Remicade only on the formulary becomes far greater. This model is somewhat conservative, because it assumes no further discounting by Pfizer for its biosimilar product. However, it also does not consider additional levels of rebating by Janssen Biotech.

A Biosimilar’s Noneconomic Benefit?

Although biosimilar manufacturers are constrained in the respect that their product has to not only mirror the structure and clinical effect of the originator biologic, it also cannot be produced in a more convenient form of administration (autoinjector vs. vial/syringe). The expectation is that the biosimilar will not be superior in any way to the originator. In a second poster presentation, Amgen researchers disputed this assertion with their biosimilar version of adalimumab. According to their findings, Amjevita® was associated with less injection-site pain compared with Humira®, based on pain scores given by clinical trial patients with moderate to severe rheumatoid arthritis. They found that pain site scores (based on a 100-mm visual analogue scale) were significantly lower at each 4-week office visit for the biosimilar.

The researchers theorize that the reason for the benefit may be the different excipients used in the biosimilar versus the originator drug.